Testing extraneous conductive part

[Ian1981]

But what is the use of testing between 2 points if they are connected together somewhere in the installation?
Like for instance a gas pipe and a known earth, but the gas pipe is connected at one end to the boiler which is connected to earth by a cpc. The cpc needs disconnecting at the boiler end then test between earth and the pipe.
That’s just one example you do not necessarily have that scenario every time of having to disconnecting anything.

 

[Midwest]

Thats the idea of this test; to discover if somehow two points are connected in someway or not.

 

[telectrix]

you could always poke it with a "live" wire. if it goes bang, it's extraneous. .....trainees.DON'T TRY THIS AT HOME>

 

[Ian1981]

Thats the idea of this test; to discover if somehow two points are connected in someway or not.

Extract taken from NAPITS site guide, the point is actually to find out if the metallic conductive part is introducing an earth potential into the installation and by testing between the earth of the installation and the conductive part, that the conductive part under test has a high enough resistance to earth that it doesn’t require bonding to the earthing arrangement of the installation

It’s

 

[static zap]

Inverse logic -Bang once then no more ? Now cured.

if it goes bang, it's extraneous.

---NOT good advice -- but get's you thinking !
22k more of a fizzle ..
(Door bell /out door LV lighting /CCTVprobably broke now)

 

[Midwest]

Extract taken from NAPITS site guide, the point is actually to find out if the metallic conductive part is introducing an earth potential into the installation and by testing between the earth of the installation and the conductive part, that the conductive part under test has a high enough resistance to earth that it doesn’t require bonding to the earthing arrangement of the installation

Fair enough. But that’s just one piece of guidance that says dis the cpc’s, against the two I posted, which suggested using cpc’s as the known earth.

Does Guidance Note 3 or 8 make any suggestions?

 

[Ian1981]

Fair enough. But that’s just one piece of guidance that says dis the cpc’s, against the two I posted, which suggested using cpc’s as the known earth.

Does Guidance Note 3 or 8 make any suggestions?

It’s only relevant to disconnect the cpc’s if required, you don’t always need to if the metallic part has not been connected together with a cpc to earth .
I don’t think gn3 covers this subject but gn5 and 8 do so I’ll have a dig out

 

[Lister1987]

you could always poke it with a "live" wire. if it goes bang, it's extraneous. .....trainees.DON'T TRY THIS AT HOME>

But I'm ok to do it in colleege....right? ?

 

[Zdb]

Thanks for all of the replies.

Interesting topic. Might have to invest in a copy of GN8.

 

[Midwest]

Thanks for all of the replies.

Interesting topic. Might have to invest in a copy of GN8.

You can tell us the answer then